This invention relates to a system for securing or attaching a bed sheet to a waterbed.
In waterbeds, due to the inherent internal wave-like motion of the water content within the mattress during use, it is difficult to retain the bed sheet over the mattress. The wave-like motion can dislodge the bed sheet from the mattress readily. Heretofore, attempts have been made to provide various arrangements for attaching a bed sheet securely to the waterbed mattress; however, many of such known arrangements either are too complex in construction or are not satisfactory in function during use. In one known arrangement, a long loose strap is provided at each corner of the bed sheet. The sheet is secured to the mattress by lifting the corners of the heavy water-filled mattress and pulling the straps under each corner one by one and letting the mattress to fall back into the bed frame. Due to the heavy weight of the water-filled mattress such operation is strenuous and awkward to carry out. Yet despite of the diffulty of attaching the bed sheet to the waterbed mattress in such an awkward manner it still can unintentionally and annoyingly separate from the mattress quite readily because of the nature of the waterbed in which the wave-like motion allows varying degrees of shifting and/or movement of the mattress.
Another known method of securing a bed sheet to the waterbed mattress is to provide fastening devices at the corners of the mattress or along the sides thereof. The fastening devices are either directly incorporated on the mattress or provided on long straps which are located underneath the mattress and with their ends extending upwards to locate at the corners of the mattress. The heavy weight of the mattress is utilized to maintain the straps in place. Associated fasteners are then incorporated at the corners of the bed sheet so that the sheet can be quickly and easily mounted in place by the engagement of the associated fastener of the sheet with the fasteners provided on the mattress. Such method provides ease of securing the sheet to the mattress; however, in the case of incorporating the fasteners to the mattress, it requires constructional modification to the latter; and in the case of using long straps, it is again necessary to lift the heavy water-filled mattress to locate such straps thereunder. Moreover, since in such arrangement, commonly the bed sheet is secured to the mattress by four fasteners provided at small areas of the four corners of the bed sheet, the force exerted on the sheet during use is concentrated at these small areas. Since the bed sheet is made of relatively non-resilient fabric, such force can cause the fabric of the sheet to tear readily at the locations of the fasteners in a very short period of time in use. Furthermore, the above methods do not take into consideration of the rail caps provided along the top of the bed frame, which can render access to these devices rather difficult.